Experimental dynamic assessment of a cable-stayed bridge

This work presents the results of the experimental dynamic assessment of the cable-stayed bridge that crosses the Garigliano river (Italy), a strategic infrastructure built in 1993 along the high-speed road connecting Naples and Rome. The bridge consists of two equal spans whose length and width are equal to 90 m and 26.1 m, respectively. The precast prestressed concrete box girder is supported by 18 couples of cables (nine couples for each span). These cables start from a central pylon whose height above the deck is equal to 30 m. The dynamic response of the deck subjected to ambient vibrations was monitored by placing several accelerometers along its longitudinal axis in order to identify the global modal characteristics (i.e., natural frequencies, mode shapes and damping ratios). The cables were equipped with accelerometers as well and the acquired measurements have been elaborated by means of some simplified analytical formulations for estimating the traction force. Finally, experimental results have been compared with initial design requirements and the outcomes of a previous dynamic monitoring campaign.